Seung Kuk Baek

Clinical Risk Factors Associated with Cervical Lymph Node Recurrence in Papillary Thyroid Carcinoma

BACKGROUND Recurrence of regional cervical lymph nodes in patients with papillary thyroid carcinoma (PTC) is not uncommon, and is an important factor affecting the quality of life. The aims of this study are to investigate the risk factors that are associated with regional lymph node recurrence by comparing a group of patients with regional lymph node recurrence with a group without lymph node recurrence, and to analyze the clinical characteristics of recurrent regional lymph nodes in PTC. METHODS A retrospective analysis was performed on 189 patients who underwent surgery for PTC. By comparing a group with recurrent cervical lymph nodes (n = 33) with a group without recurrent cervical lymph nodes (n = 156), the risk factors for cervical lymph node recurrence were investigated and the clinical characteristics of recurrent cervical lymph nodes were analyzed. RESULTS Tumor size >2 cm, presence of extrathyroid tumor spread, high T stage, and presence of lymph node metastasis were associated with regional lymph node recurrence in univariate analysis (p < 0.05). Among them, only the N stage was significantly associated with regional recurrence in multivariate analysis (p < 0.05). The disease-free survival period was shorter in the lymph node metastasis-positive group, and the 10-year disease-free survival rate was 77.8% in the lymph node metastasis-negative group and 57.9% in the lymph node metastasis-positive group (p < 0.05). Among 130 patients without lymph node metastasis, regional recurrence occurred in 13 patients (10%), and the frequent levels of regional recurrence were levels II-IV of ipsilateral neck. In the patients with lymph node metastasis, the frequent levels were levels IV-VI of ipsilateral side and level II of the contralateral side. CONCLUSION Considering the low incidence of regional lymph node recurrence and the levels with frequent regional recurrence in patients without lymph node metastasis, elective neck dissection in all cases of total thyroidectomy may be immoderate. However, if any risk factors for regional recurrence, including large tumor size, presence of extrathyroid spread, high T stage, and presence of lymph node metastasis, are detected by preoperative and intraoperative evaluation, a systematic compartment-oriented lymphadenectomy should be considered because of the high possibility of regional recurrence.

Macrophages as Cell-Based Delivery Systems for Nanoshells in Photothermal Therapy

Site-specific delivery of nanoparticles poses a significant challenge, especially in the brain where the blood–brain barrier prevents the entry of most therapeutic compounds including nanoparticle-based anti-cancer agents. In this context, the use of macrophages as vectors for the delivery of gold–silica nanoshells to infiltrating gliomas will be reviewed in this article. Gold–silica nanoshells are readily phagocytosed by macrophages without any apparent toxic effects, and the results of in vitro studies have demonstrated the migratory potential of nanoshell-loaded macrophages in human glioma spheroids. Of particular interest is the observation that, after near-infrared exposure of spheroids containing nanoshell-loaded macrophages, sufficient heat was generated to suppress spheroid growth. Collectively, these findings demonstrate the potential of macrophages as nanoshell delivery vectors for photothermal therapy of gliomas, and they certainly provide the basis for future animal studies.

Congenital internal auditory canal stenosis.

Congenital internal auditory canal stenosis is a rare cause of sensorineural hearing loss in children. A retrospective analysis including clinical manifestation and radiological findings was made for seven patients who were diagnosed with congenital internal auditory canal stenosis from 1996 to 2002. Chief presenting symptoms were hearing loss, facial nerve palsy, dizziness, and tinnitus. Hearing loss including deafness was found in five cases, vestibular function loss in four cases, and profound functional loss of facial nerve in two cases. In all cases, the diameter of the internal auditory canal was less than 2 mm on high-resolution temporal bone computed tomography (CT) scan. Two cases revealed bilateral internal auditory canal stenosis, and others were unilaterally involved cases. Congenital internal auditory canal stenosis can be an important cause of sensorineural hearing loss, facial nerve palsy, and vestibular dysfunction. High resolution temporal bone CT scan and magnetic resonance (MR) imaging were important tools for diagnosis.

Prognostic significance of vascular endothelial growth factor-C expression and lymphatic vessel density in supraglottic squamous cell carcinoma.

Regional lymph node metastases are very common findings of supraglottic cancer. The mechanism of lymphatic metastasis is as yet unknown because there have been no specific markers that could definitely distinguish lymphatic vessels from blood vessels. The aim of this study is to identify the prognostic significance of vascular endothelial growth factor‐C (VEGF‐C) expression and lymphatic vessel density (LVD) in supraglottic cancer.

The Benefits and Risks of Prophylactic Central Neck Dissection for Papillary Thyroid Carcinoma: Prospective Cohort Study.

Objectives. This study evaluated the benefits of performing prophylactic central neck dissection (CND) with total thyroidectomy (TT) in management of papillary thyroid carcinoma (PTC) patients who were clinically node-negative at presentation. Methods. A total of 257 patients with stage T1 or T2 PTC and without preoperative evidence of lymph node involvement (N0) were enrolled in this prospective study. The patients were randomly assigned to two groups: (1) a total thyroidectomy (TT) group (n = 104) or (2) a TT plus CND group (n = 153). The two groups were compared for their perioperative data, complication rates, disease recurrence rates, and clinical outcomes. Results. The two groups of patients were similar in age, sex ratio, follow-up duration, and tumor size (P = 0.227, 0.359, 0.214, and 0.878, resp.). The two groups showed similar rates of disease recurrence (3.9% in the TT group versus 3.3% in the TT plus CND group); however, complications occurred more frequently in the TT plus CND group; especially transient hypocalcemia (P = 0.043). Conclusions. Patients treated with TT plus CND had a higher rate of complications with similar recurrence rate. We believe that CND may not be routinely recommended when treating patients with PTC.

An electron microscopic study--correlation of gastroesophageal reflux disease and laryngopharyngeal reflux.

Laryngopharyngeal reflux (LPR) originates from regurgitation of gastric contents, a mechanism seemingly identical to gastroesophageal reflux disease (GERD). Some researchers postulate a connection between LPR and GERD, whereas some assert LPR is a disease apart from GERD. We examined symptoms of GERD from LPR patients, and performed gastrointestinal endoscopy and transmission electron microscopy (TEM) to evaluate GERD findings from these patients.

Prognostic Significance of the MUC1 and MUC4 Expressions in Thyroid Papillary Carcinoma

Objectives: The aim of the present study was to examine the expressions of mucin genes MUC1 and MUC4 and to evaluate the difference of their expressions in normal thyroid tissue, follicular adenoma, and papillary carcinoma. Furthermore, we aimed to estimate their prognostic significance in papillary carcinoma.

Decreased expression of E-cadherin and ZO-1 in the nasal mucosa of patients with allergic rhinitis: Altered regulation of E-cadherin by IL-4, IL-5, and TNF-alpha.

Background Allergic rhinitis is a chronic nasal inflammatory disease mediated by an immunoglobulin E mediated process to environmental allergens. Although atopy is a potent predisposing risk factor for allergic rhinitis, local tissue susceptibilities are inevitable for disease expression. The nasal epithelium maintains tissue homeostasis by providing a physical barrier controlled by epithelial junctional proteins. However, the expression of epithelial junctional proteins has not been studied in patients with allergic rhinitis. We sought to elucidate the expression and the regulation of epithelial junctional proteins in the nasal epithelium of patients with allergic rhinitis. Methods The expression of E-cadherin and zonula occludens (ZO) 1 in epithelium of turbinate was measured by using real-time polymerase chain reaction, Western blot, and immunohistochemical assays, and was compared between control subjects and patients with allergic rhinitis. In addition, the expression levels of E-cadherin and ZO-1 were determined in cultured epithelial cell treated with interleukin (IL) 4, IL-5, tumor necrosis factor (TNF) alpha, and interferon gamma. Results The expression and the immunoreactivity of E-cadherin and ZO-1 were decreased in the nasal epithelium of patients with allergic rhinitis. Interestingly, the stimulation of cultured epithelial cells with IL-4, IL-5, and TNF-alpha resulted in downregulation of E-cadherin expression only in cultured epithelial cells of patients with allergic rhinitis, whereas E-cadherin expression in cultured epithelial cells of controls was not affected by stimulation with the same panel of cytokines. Conclusion Decreased expression of epithelial junctional proteins was found in patients with allergic rhinitis. The disruption of epithelial integrity by IL-4, IL-5, and TNF-alpha in vitro indicated a possible role for these cytokines in the pathogenesis of patients with allergic rhinitis.

Clinical efficacy of primary tumor volume measurements: comparison of different primary sites.

Objectives The purpose of study was to determine the clinical efficacy of primary tumor volume measurements of different primary sites in the oropharynx compared to the oral cavity. Methods A retrospective analysis of 85 patients with oral cavity or oropharynx cancer. The tumor area was manually outlined from axial magnetic resonance (MR) series. The software calculated the tumor volumes, automatically. The values of the primary tumor volumes were then subdivided into separate groups (≤3,500 mm3, >3,500 mm3). Results The prognostic indicators were the cT and cN (oral cavity); age, primary site, cT, cN, and primary tumor volume (oropharynx) on the univariate analysis. There was no significant prognostic factor for oral cavity cancer on the multivariate analysis. Primary site, cN, and primary tumor volume were independent prognostic indicators for oropharynx cancer by multivariate analysis. Conclusion Primary tumor volume measurement is a reliable way to stratify outcome, and make up for the weak points in the American Joint Committee on Cancer staging system with oropharynx cancer.

Cyclooxygenase 1 and 2 expressions in the human thyroid gland

We investigated the expression of COX-1 and COX-2 in normal thyroid tissue, follicular adenoma and well-differentiated thyroid carcinomas and evaluated the difference in COX-1 and COX-2 expression. Ten normal thyroid tissues, ten follicular adenomas, ten papillary carcinomas and ten follicular carcinomas were analyzed by semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) for expression of COX-1 and COX-2 mRNA. In addition, immunohistochemical staining was performed to find the expression of the two enzymes in normal thyroid tissues and thyroid neoplasia. Expression of COX-1 mRNA in the normal thyroid tissues, follicular adenomas and both well-differentiated carcinomas was similar and weak. However, COX-2 mRNA was strongly expressed in the well-differentiated carcinomas compared to those of normal thyroid tissue and follicular adenoma.